From 1943-1945, Chaetostoma anale was described three times under three different names by the same author, Henry Weed Fowler, who was Curator of Ichthyology at the Academy of Natural Sciences in Philadelphia from 1934 to 1965. Following the rules of Zoological Nomenclature, only the first of the names applied to this species is valid. The currently invalid junior synonyms are C. alternifasciatum and C. vagum.
In 2017, I was fortunate to be able to collect specimens, tissues, and photos of this species from the type locality, headwaters of the Caqueta River near Florencia, Colombia, with the assistance of Colombian biologists Armando Ortega Lara, Francisco Villa, Cristhian Conde, and Felipe Arteaga, and Peruvian biologist Vanessa Meza Vargas.
We were only able to collect immature of this species, but as the species grows, males develop relatively elaborate sexual dimorphisms, including an enlarged snout, fleshy folds of skin on fin rays, and elongation of pelvic and anal fin rays. See a previous post on Chaetostoma dermorhynchum for an illustration of such dimorphism. This suite of distinctive, sexually dimorphic traits unite a clade of Chaetostoma species now known as the C. anale clade. - Nathan Lujan, June 2021
